From 41903d42aee8c4823b190b6b965a2c9ceb0f0699 Mon Sep 17 00:00:00 2001
From: Shunsuke Shimizu <grafi@grafi.jp>
Date: Thu, 4 Jul 2019 13:03:24 +0900
Subject: [PATCH] explicitly search cblas_sgemm in ATLAS and OpenBLAS target

---
 chainerx_cc/cmake/FindBLAS.cmake | 38 +++++++++++++++++---------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/chainerx_cc/cmake/FindBLAS.cmake b/chainerx_cc/cmake/FindBLAS.cmake
index 7e2462eaf3a5..ee628891027a 100644
--- a/chainerx_cc/cmake/FindBLAS.cmake
+++ b/chainerx_cc/cmake/FindBLAS.cmake
@@ -171,21 +171,6 @@ macro(Check_Fortran_Libraries LIBRARIES _prefix _name _flags _list _thread)
     mark_as_advanced(${_prefix}${_combined_name}_WORKS)
     set(_libraries_work ${${_prefix}${_combined_name}_WORKS})
   endif()
-  if(_libraries_work)
-    # NOTE: ChainerX uses CBLAS API. Search `libcblas.so` if CBLAS functions are
-    # not provided in the blas library found.
-    set(CMAKE_REQUIRED_LIBRARIES ${_flags} ${${LIBRARIES}} ${_thread})
-    check_function_exists("cblas_sgemm" ${_prefix}${_combined_name}_HAS_CBLAS)
-    if(NOT ${_prefix}${_combined_name}_HAS_CBLAS)
-        find_library(${_prefix}${_combined_name}_CBLAS_LIBRARY cblas)
-        if(${_prefix}${_combined_name}_CBLAS_LIBRARY)
-          set(${LIBRARIES} ${${LIBRARIES}} ${${_prefix}${_combined_name}_CBLAS_LIBRARY})
-        else()
-          set(_libraries_work FALSE)
-        endif()
-    endif()
-    set(CMAKE_REQUIRED_LIBRARIES)
-  endif()
   if(_libraries_work)
     if("${_list}" STREQUAL "")
       set(${LIBRARIES} "${LIBRARIES}-PLACEHOLDER-FOR-EMPTY-LIBRARIES")
@@ -424,10 +409,11 @@ endif ()
 if (BLA_VENDOR STREQUAL "OpenBLAS" OR BLA_VENDOR STREQUAL "All")
   if(NOT BLAS_LIBRARIES)
     # OpenBLAS (http://www.openblas.net)
+    # ChainerX modification: check `cblas_sgemm`.
     check_fortran_libraries(
       BLAS_LIBRARIES
       BLAS
-      sgemm
+      cblas_sgemm
       ""
       "openblas"
       ""
@@ -435,6 +421,21 @@ if (BLA_VENDOR STREQUAL "OpenBLAS" OR BLA_VENDOR STREQUAL "All")
   endif()
 endif ()
 
+if (BLA_VENDOR STREQUAL "OpenBLAS" OR BLA_VENDOR STREQUAL "All")
+  if(NOT BLAS_LIBRARIES)
+    # ChainerX modification: search libcblas if `cblas_sgemm` not found.
+    # OpenBLAS might be built without cblas functions.
+    check_fortran_libraries(
+      BLAS_LIBRARIES
+      BLAS
+      cblas_sgemm
+      ""
+      "openblas;cblas"
+      ""
+      )
+  endif()
+endif ()
+
 if (BLA_VENDOR STREQUAL "FLAME" OR BLA_VENDOR STREQUAL "All")
   if(NOT BLAS_LIBRARIES)
     # FLAME's blis library (https://github.com/flame/blis)
@@ -452,12 +453,13 @@ endif ()
 if (BLA_VENDOR STREQUAL "ATLAS" OR BLA_VENDOR STREQUAL "All")
   if(NOT BLAS_LIBRARIES)
     # BLAS in ATLAS library? (http://math-atlas.sourceforge.net/)
+    # ChainerX change: check `cblas_sgemm` and search libcblas.
     check_fortran_libraries(
       BLAS_LIBRARIES
       BLAS
-      dgemm
+      cblas_sgemm
       ""
-      "f77blas;atlas"
+      "f77blas;atlas;cblas"
       ""
       )
   endif()